Lophotrochozoa (trochophora larvae; spiral cleavage)

Ectoprocta (Bryozoa)
Moss animal

Entoprocta (Kamptozoa)
Goblet worm

Platyhelminthes - Catenulida
Flatworm

Platyhelminthes - Rhabditophora
Flatworm

Platyhelminthes - Rhabditophora - Neodermata
Parasitic flatworm

Some parasitic flatworms have very complex life cycles
feeding off different hosts during different stages of their life
 

Chaetognatha